The present invention relates to an industrial and/or medical endoscope apparatus and, more particularly, to an inserting instrument for such endoscope apparatus, which is utilized as a guiding instrument for guiding a flexible inserting portion of an endoscope into an object to be inspected and/or as a measuring instrument for measuring a size of a part within the object.
In recent years, an industrial endoscope apparatus has widely been utilized in various kinds of industrical fields. The reason for this is that, in the inspection and the like of an interior of a machine such as, for example, a jet engine, the interior of the machine as an object to be inspected can be viewed without disassembling the machine, and this makes it possible to reduce the working time and to improve the working performance or efficiency.
A general endoscope apparatus of this kind referred to above comprises an endoscope which includes an operating body and a flexible inserting portion extending from one end of the operating body. An ocular portion is provided at the other end of the operating body. In use, the inserting portion of the endoscope is inserted into an interior of an object to be inspected, through an opening provided in the object. The interior of the object is viewed by the ocular portion through a viewing optical system provided at the inserting portion.
In case where the interior of the object to be inspected is complicated in configuration and one or more restrictions are formed within the object on the way to a part to be inspected, however, should an attempt be made to insert the inserting portion alone, the distal end of the inserting portion would often sag under its own weight, because of the flexibility of the inserting portion, and it would be difficult to insert the inserting portion to the desired part to be inspected. In such case, it has conventionally been proposed that the inserting portion of the endoscope is inserted through a guide tube harder than the inserting portion; the guide tube is precedently passed through the restrictions while determining the passing direction of the guide tube by the inserting portion; and, subsequently, the inserting portion is advanced through the guide tube and is projected from the distal end of the guide tube, to permit the inserting portion to view the part to be inspected. However, the guide tube is required to have its outer diameter greater than that of the inserting portion, and the increase in diameter makes the inserting operation difficult accordingly. This would cause the operability to be deteriorated. In addition, if the diameter of the restrictions within the object to be inspected is less than that of the guide tube, it is no longer possible to use the guide tube.
In view of the above, a further proposal has been made in which a guide channel is formed which extends through the operating body and the inserting portion of the endoscope; a guiding instrument is inserted from an inserting opening provided in the operating body into and through the guide channel so as to have a distal end projected from the distal end of the inserting portion; an engaging member provided at the distal end of the guiding instrument is brought into engagement with the restriction within the object to be inspected; and, subsequently, the inserting portion of the endoscope is advanced along the guiding instrument. A known guiding instrument of this kind is comprised of a thin or fine tube and a balloon which is attached to a distal end of the tube and which serves as an engaging member. The balloon is maintained withered until the distal end of the guiding instrument reaches the restriction within the object to be inspected. Fluid such as water, air or the like is injected into the balloon to inflate the same when the distal end of the guiding instrument reaches the restriction, to thereby bring the inflated balloon into engagement with the restriction. Another known guiding instrument is comprised of a helical tube, and a hook which serves as an engaging member and which is attached to the distal end of the helical tube. The hook is brought into engagement with the restriction within the object to be inspected.
However, the above-described, conventional guiding instruments for the inserting portion of the endoscope have had the following problems:
In case of the guiding instrument employing the balloon, there is a problem in the durability of the balloon. Specifically, should the balloon be damaged and broken by sharp-pointed projections such as flashes or fins formed within the object, it would no longer be possible to inflate the balloon and this would make it impossible to bring the balloon into engagement with the restriction within the object.
In case of the guiding instrument employing the hook, it is not possible to vary or alter the configuration of the hook, unlike the balloon, before and after the engagement of the hook with the restriction and, therefore, it is extremely difficult to ensure the engagement of the hook with the restriction.
Apart from the above, it has often been desired and required to measure a size or dimension of a part such as polyp within a body cavity or a size of a part within a machine. A measuring instrument used for this purpose is disclosed in Japanese Utility Model Application Laid-Open No. 57-7501 laid open to public inspection on Jan. 14, 1982, for example. The measuring instrument disclosed in the Japanese utility model application comprises an outer tubular envelope, a wire extending through the envelope, a pair of elongated, curved spring members having their respective one ends connected to a distal end of the wire and the respective other ends spaced away from each other, and a collapsible or foldable strap-like scale having carried thereon graduations and extending between the respective other ends of the spring members.
In use of the measuring instrument, the inserting portion of the endoscope is inserted into an object to be inspected and the distal end of the inserting portion is located adjacent a part to be measured. Subsequently, under such a condition that the pair of spring members and the scale are previously retracted into the distal end of the outer envelope so that the other ends of the respective spring members are located close to each other against their respective spring forces and the scale is collapsed or folded, the outer envelope is inserted from the inserting opening provided in the operating body of the endoscope, into and through the inserting portion thereof so as to have the distal end projected from the distal end of the inserting portion. Subsequently, the wire is operated to project the spring members from the distal end of the outer envelope. The other ends of the respective spring members are spaced apart away from each other under their respective spring forces to allow the strap-like scale to be stretched straight. The stretched scale is approached to the part to be measured, and the graduations on the scale are viewed and read through a viewing optical system at the distal end of the inserting portion.
Since, however, it is necessary for the abovedescribed conventional measuring instrument for the endoscope, to retract and house the scale and the spring members into and within the distal end of the envelope, the diameter of the envelope is inevitably increased. This results in an enlargement of the diameter of the inserting portion of the endoscope through which the envelope is inserted.